Audie Murphy plays Joe Maybe, an outlaw who is mistaken for U.S. Marshall Jim Noonan, when he assumes the man's identity after his death. Pretending to be Noonan, Maybe is appointed sheriff of Webb City, a rough river town, after local lawmaker Judge Kyle (Walter Matthau), takes a shine to him. The only reason Maybe goes along with the ruse is to gain easy access to the town bank and plan a robbery. This scheme goes dangerously awry when Tessa (Gia Scala), a former flame from New Orleans, shows up in town and is persuaded to pose as his wife. The couple's masquerade is further complicated by the arrival of Sam Teeler (Henry Silva), Maybe's rival in crime, who plans to rob the bank with his own gang of outlaws.